C++基于socket的单线程服务器客户端聊天程序（TCP）

编写服务器端的基本步骤：

1. 初始化winsock；
2. 创建socket；
3. 绑定socket；
4. 在socket上对客户端进行监听；
5. 接受客户端的连接；
6. 收发消息；
7. 断开连接；

//服务器端
#include <iostream>
#include "winsock2.h"
#include "string.h"
using namespace std;

#pragma comment(lib,"ws2_32.lib")

int main()
{
    //初始化socket
    WSADATA wsaData;//改结构体包含winsock实现的信息
    if (WSAStartup(MAKEWORD(2, 2), &wsaData)  !=  0)
    {
        cout<<"WSAStratup error!"<<endl;
        exit(1);
    }
    //建立socket
    SOCKET servers = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
    if(servers == INVALID_SOCKET)
    {
        cout<<"Failde to create server socet!Error code:"<<WSAGetLastError()<<endl;
        WSACleanup();
        exit(1);
    }
    //绑定socket
    SOCKADDR_IN sin;
    sin.sin_family = AF_INET;
    sin.sin_port = htons(8888);
    sin.sin_addr.S_un.S_addr = INADDR_ANY;
    if (bind(servers, (LPSOCKADDR)&sin, sizeof(sin)) == SOCKET_ERROR)
    {
        cout<<"Failed to bind server socket!Error code:"<<WSAGetLastError()<<endl;
        WSACleanup();
        exit(1);
    }
    //监听socket
    if (listen(servers, 10) == SOCKET_ERROR)//消息等待队列为10
    {
        cout<<"Failed to listen server socket!Error code:"<<WSAGetLastError()<<endl;
        WSACleanup();
        exit(1);
    }
    cout<<"Server started successfully..."<<endl;
    //接收客户端请求
    SOCKET sclient;
    SOCKADDR_IN clientAdd;
    int cAddlen = sizeof(clientAdd);
    char buf[255];//缓冲区  大小为255
    char sendbuf[255];//发送缓冲区
    sclient = accept(servers, (LPSOCKADDR)&clientAdd, &cAddlen);
    if (sclient == SOCKET_ERROR)
    {
        cout<<"Failde to accept client!Error code:"<<WSAGetLastError()<<endl;
        WSACleanup();
        exit(1);
    }
    printf("接收到一个连接：%s\n", inet_ntoa(clientAdd.sin_addr));
    //接收和发送数据
    while (true)
    {
        memset(buf,0,sizeof(buf));
        memset(sendbuf,0,sizeof(sendbuf));
        int res = recv(sclient, buf, sizeof(buf), 0);
        if (res > 0)
        {
            cout<<"client:"<<buf<<endl;
        }
        else if(res == 0)
        {
            cout<<"Connect close..."<<endl;
            break;
        }
        else
        {
            cout<<"Failed to receive message from client!Error code:"<<WSAGetLastError()<<endl;
            closesocket(sclient);
            return 0;
        }
        cout<<"server:";
        gets(sendbuf);
        if (strcmp(sendbuf, "bye") == 0)
        {
            cout<<"Client requests to close the connection..."<<endl;
            break;
        }
        res = send(sclient, sendbuf, strlen(sendbuf), 0);
        if(res == SOCKET_ERROR)
        {
            cout<<"Failed to send message to client!Error code:"<<WSAGetLastError()<<endl;
            closesocket(sclient);
            return 0;
        }
    }
    //关闭socket连接
    closesocket(sclient);
    closesocket(servers);
    cout<<"socket close..."<<endl;
    WSACleanup();
    return 0;
}

编写客户端的基本步骤:

1. 初始化winsock；
2. 创建socket；
3. 连接服务器；
4. 收发消息；
5. 断开连接；

//客户端
#include <iostream>
#include "winsock2.h"
#include "string.h"
using namespace std;

#pragma comment(lib,"ws2_32.lib")

int main()
{
	//初始化winsock
	WSADATA wsaData;
	if (WSAStartup(MAKEWORD(2,2),&wsaData) != 0)
	{
		cout<<"WSAStratup error!"<<endl;
		exit(1);
	}
	//创建socket
	SOCKET client = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if(client == INVALID_SOCKET)
	{
		cout<<"Failde to create client socet!Error code:"<<WSAGetLastError()<<endl;
		WSACleanup();
		exit(1);
	}
	//连接服务器
	SOCKADDR_IN sin;
	sin.sin_family = AF_INET;
	sin.sin_port = htons(8888);//服务器端口
	sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");//服务器IP
	if (connect(client, (LPSOCKADDR)&sin, sizeof(sin)) == SOCKET_ERROR)
	{
		cout<<"Failde to connect with server!Error code:"<<WSAGetLastError()<<endl;
		WSACleanup();
		exit(1);
	}
	char sendbuf[255];
	char recbuf[255];
	//收发消息
	while (true)
	{
		memset(sendbuf,0,sizeof(sendbuf));
		memset(recbuf,0,sizeof(recbuf));
		cout<<"client:";
		gets(sendbuf);
		int res = send(client, sendbuf, strlen(sendbuf),0);
		if (strcmp(sendbuf, "bye") == 0)
			break;
		if(res == SOCKET_ERROR)
		{
			cout<<"Failed to send message!Error code: "<<WSAGetLastError()<<endl;
            closesocket(client);
            WSACleanup();
            exit(1);
		}
		res = recv(client, recbuf, 255,0);
		if (res > 0)
		{
			cout<<"server:"<<recbuf<<endl;
		}
		else
		{
			cout<<"Failed to receive message from server!Error code:"<<WSAGetLastError()<<endl;
			closesocket(client);
			return 0;
		}
	}
	//关闭socket
	closesocket(client);
	WSACleanup();
	cout<<"socket close..."<<endl;
        return 0;
}